Ecologists have been saying for decades now that the world is in the midst of a biodiversity crisis. Hundreds of species are vanishing every year, thanks to assaults to the environment that include deforestation, overfishing, toxic pollution and, increasingly, climate change — the lethal icing on an already poisoned cake. Twenty years ago, 150 countries signed the international Convention on Biodiversity to try and hold back the tide of extermination, but without much success: Scientists are now saying the planet may be going through its sixth mass extinction in the past 540 million years, and the first caused by humans.

But experts haven’t been so good at explaining exactly why this is such a terrible thing. “Most of the arguments have been based on the idea that biodiversity has some intrinsic value,” said Bradley Cardinale, an ecologist at the University of Michigan, in an interview yesterday. “We like it. It’s pretty. The Pope says we should conserve God’s creation. Maybe we’ll find new medicinal plants in the rainforest.”

In a new paper just published in Nature, however, Cardinale and 17 colleagues have made a much more solid argument. “We’re saying that biodiversity does things that are really important,” he said. “There’s really strong evidence that if we lose biodiversity, it will, among other things, affect food production and fresh water supplies and increase the frequency of pests and diseases that affect crops and animals.”

The paper is what’s known as a meta-analysis: the 18 authors, all of them leaders in the field of ecology, gathered more than a thousand studies published over the past 20 years that looked at biodiversity from a myriad of angles. Then they looked at whether differences in biodiversity affected an ecosystem’s ability to do useful things — the ability of a forest to remove carbon from the atmosphere, for example, or supply wood for construction; the ability of bacteria in a stream to neutralize pollutants; the ability of natural predators and parasites to control agricultural pests.

The answer, it turns out, is yes, to these and many other similar questions. In many cases, it boils down to two primary reasons. The first is that the most diverse ecosystems tend to include what the scientists call “super species.” Say you’re talking about the capacity of a diverse forest to produce wood, or to take carbon from the air, Cardinale said.

“About 50 percent of that effect will come from a single, highly productive species,” he said. The other half comes from a wide variety of other species that occupy different niches, grow at different rates. “It’s like the Miami Heat,” he said. “Half of their productivity comes from LeBron James, but without a strong supporting cast of players, that would not be enough.”

This 50-50 rule is one of six major “consensus statements” all of the scientists were able to agree on, even though some of the 18 disagree with others on narrower details. The others, paraphrased:

The evidence is unequivocal that biodiversity loss makes ecosystems less efficient at producing biomass and at decomposing and recycling biologically essential nutrients.

The evidence is mounting that biodiversity increases the stability of these ecosystem functions

The impact of biodiversity on any single biological process within an ecosystem accelerates as biodiversity loss increases.

Loss of diversity over many trophic levels — that is, levels on the food chain — can be more damaging than the loss of diversity within trophic levels

The effects of biodiversity loss depend on what functions the lost species served in an ecosystem. In other words, some species are more crucial than others.

What the new analysis doesn’t do is put a dollar figure on how the loss of biodiversity impacts us. “We’re not at a point where we can do this realistically,” Cardinale said. “It’ll probably be five or 10 years before we have enough information.”

It’s also unclear at this point how quickly and easily ecosystems can readjust after they go through major species loss. “The term ‘fragile ecosystem’ is much more common in pop environmentalism than in science,” Cardinale said. “Ecosystems can be very robust.” The area around Chernobyl, he noted, is thriving. “It’s a great example of resilience and robustness. But at this point, we don’t know what the norm is.”

One way or another, Cardinale said, “biology will go on. But we don’t know whether it will go in a way that’s good for humanity.”

Michael D. Lemonick is the Senior Science Writer for Climate Central. This piece was originally published at Climate Central and reprinted with permission.

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9 Responses to How Biodiversity Loss is Like LeBron James & Miami Heat

A good example of our problems can be found in the forests of the Pacific Northwest. Ancient forests there often contained over 1,000 tons of biomass, consisting of myriad life forms. When the land is converted to tree farms, as most of it has, a lot of bad things happen. Biomass is down to about 150 tons an acre. Microclimates become hotter, and water is dirtier and contains fewer fish. Disturbances such as forest fires and insect infestations are not resisted as well.

Biologists know this, but land managers are charged with “mixed use”, and dominate planning. Cash payments in the form of lumber are more highly valued than fish, clean water, and resiliency.

If we make this conversion, more lumber will actually become available, but mechanized clearcutting on short “rotations” is driven by the discount rate. We need to put incentives in place to change this- as Sweden and Japan already have.

Being humanity is at the TOP of the food chain, it is impossible for me to see how the loss of biodiversity can be helpful to humanity. One only needs to go where biodiversity is the lowest and see how many folks live there without the import of exploited resources from afar. Even the cells in your body are outnumbered ~10 to 1 by bacteria. Who is in the control room?

Leif, Someone suggested to me that we think of ourselves at or near the bottom of the food chain. Energy from sunlight trickles down through plant, animal, brewer’s yeast, gut biota and the like until at last we get some. Energetically, in thermodynamics, we are closer to the bottom, where it is convenient to be omnivores, chowing down on or at least sampling darn near everything that comes our way.
That opportunistic behavior of acquiring stuff seems to be proving to be our undoing, along with the undoing of other life.

Good point Joan. Then we remove ourselves from the loop with cremation or pumping our veins full of formaldehyde. Very strange. What comes around, goes around. There is an old sailor’s adage, “Never go to sea in a boat you would not be proud to have as your coffin.”I am not proud to have the 6th great extinction on my watch, by my hands. I am doing all I can to keep a line fast to the dock…

Cardinale points out that it will take some more years to quantify the ‘dollar impacts’ of biodiversity loss. He’s being specific regarding roles of biodiversity, and it’s important to distinguish that from other work on establishing the dollar impacts of environmental losses.

I believe that classification in terms of species and extinctions has put us in a “coolie” frame of mind where we’re unable to see the tragedy of individual deaths. If you recall, a white South African traveler had Mahatma Gandhi thrown off the train because he viewed all brown colored people as “coolies” and therefore undeserving of first-class train travel. This lack of acknowledgement of his individual self prompted Gandhi to dust himself off and lead 300 million Indians to non-violently evict the British from India.

Perhaps, we are all in the position of that white South African traveler, unable to feel the plight of the billions of individual lives being lost in the 30 million acres of tropical forests being destroyed each year. I believe that until we see every one of those unnatural deaths as a tragedy, we won’t be able to reverse the destruction of the forests and avoid the coming crunch.

Humanity is confronter with sensory overload and has shut down. We can see it when confronted with a disaster that requires donated dollars to help mitigate. I believe that there has been a clear drop in public volunteer donations. Of course a lot of that can be attributed to many more living from hand to mouth as well.

In the tropical forests carbon is mostly in living organisms with very little carbon in detritus or soil, while in temperate zones and the high latitudes the carbon sequestration split (past tense) between living organisms (standing biomass) and organic soils. When biodiversity is lost both the biomass declines and the organic soils are vulnerable to several kinds of loss.

The situation in the Plains states would be far different this year if there were more of the original tall grass and short grass prairies left. Both ecosystems are adapted to periods of drought and fire.